Electronic ballast for a fluorescent lamp

Abstract

An electronic ballast for a fluorescent lamp with low voltage power supply is composed of a wave filter circuit, a rectifier circuit, a generation and control circuit of high frequency and an ignition circuit of the lamp tube. The output end of the wave filter circuit is connected to the input end of the rectifier circuit. The output end of the rectifier circuit is connected to the generation and control circuit of high frequency and the ignition circuit of the lamp tube. The feedback transformer is put into the output circuit of the generation and control circuit of high frequency.

What is claimed is:  
     
       1. An electronic ballast for a fluorescent lamp with low-voltage power supply comprising a wave filter connected with its output to the input of a rectifier circuit which is connected with its output to the input of a generation and control circuit of high frequency to the output end of which is connected to a resonance circuit composed of a choke (L) and a capacitor (C 7 ), and an ignition circuit; the generation and control circuit including two solid state switches and feedback transformer means (B 1 ) which is put with its primary circuit into the output of the generation and control circuit; at least one coil (B 1 - 1 ) of the primary circuit of the feedback transformer means for supplying feedback to one of the solid state switches is connected between the joint of the choke (L) and the capacitor (C 7 ) of the resonance circuit and one contact of the fluorescent lamp (F). 
     
     
       2. Electronic ballast according to  claim 1 , characterized in that 
       the feedback transformer means comprises two transformers and said primary feedback coil (B 1 - 1 ) is connected on said two transformers between the joint of said choke (L) and said capacitor (C 7 ) of the resonance circuit and one contact of the fluorescent lamp (F).  
     
     
       3. Electronic ballast according to  claim 1 , characterized in that 
       the feedback transformer means comprises one primary feedback coil (B 1 - 1 ) connected with a two holes transformer.  
     
     
       4. Electronic ballast according to  claim 1 , characterized in that 
       the primary feedback transformer means comprises two transformers connected with one transformer in the front and one transformer at the back of said choke (L).  
     
     
       5. Electronic ballast according to  claim 1 , characterized in that 
       the primary feedback means comprises one transformer including two primary feedback coils (B 1 - 1 , B 1 - 4 ) one coil (B 1 - 4 ) being connected in the front and one coil being connected to the back of said choke (L).